Bis-oxalic acid ester amides for use as ultraviolet stabilizers

ABSTRACT

The present invention provides a process for protecting organic materials that can be damaged by ultraviolet light from the effects of ultraviolet rays, characterized in that a bis-oxalic acid amide ester is incorporated with, or applied to the surface of the materials to be protected, or a filter layer containing the bis-oxalic acid amide esters is placed in front of said materials, the said bis-oxalic acid amide ester corresponding to the formula A1-O-CO-CO-NH-W1-NH-CO-CO-O-B1 in which A1 and B1 are identical or different and each represents an organic residue and should not displace the absorption maximum of these compounds to values above 370 Mu ; W1 represents an organic residue and should not displace the absorption maximum of these compounds to values above 370 Mu ; W1 represents an organic residue, and X1 represents an alkylene group containing one to four carbon atoms or a bridge member -O-, -S-, -N- or -SO2-. Furthermore the invention discloses a certain class of novel symmetric bis-oxalic acid amide esters as defined by formula (6) of the specification and a process for the manufacture of the symmetric bis-oxalic acid amide esters defined above.

United States Patent Luethi, et al.

[ Feb. 1, 1972 BlS-OXALIC ACID ESTER AMIDES FOR USE AS ULTRAVIOLETSTABILIZERS [72] Inventors: Christian Luethi, Muenchenstein; Hans RudoltBiland, Gelterkinden; Max Duennenberger, Frenkendorf, all of SwitzerlandPrimary Examiner-Charles E. Van Horn Assistant Examiner-J P. BrammerAttorney-Harry Goldsmith, Joseph G. Kolodny, Bryant W. Brennan andEdward J Sites [57] ABSTRACT The present invention provides a processfor protecting organic materials that can be damaged by ultravioletlight from the effects of ultraviolet rays, characterized in that abis-oxalic acid amide ester is incorporated with, or applied to thesurface of the materials to be protected, or a filter layer containingthe bis-oxalic acid amide esters is placed in front of said materials,the said bis-oxalic acid amide ester corresponding to the formula:

in which A, and B, are identical or different and each represents anorganic residue and should not displace the absorption maximum of thesecompounds to values above 370 m W represents an organic residue and X,represents an allgyle ne groupcontaining l to 4 carbon atoms or a bridgemember -O-, -S-, -N or --SO-,,.

Furthermore the invention discloses a certain class of novel symmetricbis-oxalic acid amide esters as defined by formula (6) of thespecification and a process for the manufacture of the symmetricbis-oxalic acid amide esters defined above.

6 Claims, No Drawings BlS-OXALIC ACID ESTER AMIDES FOR USE ASULTRAVIOLET STABILIZERS The present invention is concerned with thestabilization of organic materials, especially towards the effects ofultraviolet rays, by means of bis-oxalic acid ester amides, and providesprocesses for their manufacture as well as an important group of newbis-oxalic acid ester amides that are valuable to the purpose mentioned.

Accordingly, the invention provides a process for protecting organicmaterials that may be damaged or destroyed by ultraviolet rays from theinfluence of ultraviolet rays, by incorporating with the material to beprotected bis-oxalic acid ester amides of the following definition, orby applying them to the surface of said materials or by placing in frontof the material to be protected a filter layer containing suchbis-oxalic acid ester amides. The bis-oxalic acid ester amides to beused for such protection correspond in their most general form to theformula (l) A,O-COCONH-W,-Nl-lCO-C-O- 1 in which A, and B, are identicalor different and each represents an alkyl, alkenyl, cycloalkyl, aralkylor aryl group; these groups may contain further substituents and shouldnot displace the absorption maximum of the said compounds to valuesabove 370 mu; W, represents a phenylene, diphenylene, naphthyleneresidue or a residue of the formula (Z 1) in O and the phenylene groupsof these residues may contain one or two substituents Z,,Z, being analkyl or alkoxy group containing one to four carbon atoms, a halogenatom or an SO H group; m=0, l or 2, and X, represents an alkylene groupcontaining one to four carbon atoms or a bridge member O, S*, ITJ orSO,.

As further substituents of the residue A, and B, (or of the residues Adefined below) there may be used within the definition of the aboveformula especially alkyl groups, halogen atoms, alkoxy, alkoxyalkoxy,cyano or tertiary amino groups.

When X in the above formula represents a nitrogen bridge member l,-l, itshould be borne in mind that the free valency of this bridge member issaturated in most cases by a hydrogen atom or an alkyl group containingone to four carbon atoms.

Of paramount importance because of the greater ease with which they canbe prepared are symmetric bis-oxalic acid amide esters of the formula(2) A 0-CO-CONHW,--NH-CO-COO- 2 in which A represents an alkyl, alkenyl,cycloalkyl or aralkyl radical containing up to carbon atoms, which doesnot displace the absorption maximum of these compounds to a value above370 my, and which may, ifdesired, contain further substituents, and W,represents a phenylene, diphenylene, naphthylene residue or a residueand the phenylene groups of these residues may contain one or twosubstituents Z,,Z, being an alkyl or alkoxy group containing one to fourcarbon atoms, a halogen atom or an SO H group; m=0, l or 2, and X,represents an alkylene group containing one to four carbon atoms or abridge member O-, S-, -NH or SO The identical substituents as shown forformula (1) may be contained also in the abovementioned residue AAccording to the preferred variant of the process of this inventionsymmetric bis-oxalic acid amide esters are used that correspond to theformula (3) A,,--OCO--CONH-W,--NH-COCO-O in which A,, represents analkyl group containing one to l8 carbon atoms, a phenylalkyl group whosealkyl residue contains one to four carbon atoms, an alkoxyalkyl groupcontaining one to 12 carbon atoms and preferably one to three -O-bridges, an alkenyl group containing one to four carbon atoms or acyclohexyl group, and W represents a l,3- or l,4-phenylene group, a4,4'-diphenylene group, a 1,4- or 1,5- naphthylene group or a group inwhich X is a bridge member SO or a linear or branched alkylene groupcontaining one to four carbon atoms, and phenylene nuclei of the saidgroupings may contain one or two substituents Z alkyl or alkoxy groupwith one to four carbon atoms or halogen) and "i=0, 1 or 2.

In a technically especially progressive variant symmetric bis-oxalicacid amide esters are used that correspond to the formula (4)A;,-O-COCO--NH\V,,-Nl-lCOCOO in which A, represents an alkyl groupcontaining one to 18 carbon atoms, a phenylalkyl group whose alkylresidue contains one to four carbon atoms, an alkoxyalkyl groupcontaining one to l2 carbon atoms and preferably one to three O bridges,an alkenyl group containing one to four carbon atoms or a cyclohexylgroup; W represents a 1,3- or l,4-phenylene group, a 4,4'-diphenylenegroup, a l,4- or 1,5-naphthylene group, and phenylene nuclei of the saidgroupings may contain one or two substituents Z 2 being an alkyl oralkoxy group containing one to four carbon atoms or a halogen atom.

A subgroup of the compounds to be used according to this inventioncomprises symmetric bis-oxalic acid amide esters of the formula in whichA, represents an alkyl group containing one to six carbon atoms and W al,3- or l,4-phenylene group, a 4,4-

diphenylene group, a l,4- or l,5-naphtl1ylene group ofa group in which Xrepresents a bridge member -SO or a linear or branched alkylene groupcontaining one to four carbon atoms, and phenylene nuclei of the saidgroupings may contain one or two substituents Z- Z, being an alkyl oralkoxy group containing one to four carbon atoms or a halogen atom, and"i=0, l or 2.

It is also possible to use with advantage the new bis-oxalic acid amideesters of the formula (6) A,,O-CO-CONHW -NH-COCOO- in which A,represents an alkyl group containing seven to l8 carbon atoms, aphenylalkyl group whose alkyl residue contains one to four carbon atoms,an alkoxyalkyl group containing one to eight carbon atoms and one tothree oxygen bridges, an allyl group or a cyclohexyl group, and Wrepresents a 1,3- or l,4-phenylene group, a 4,4'-diphenylene group, al,4- or 1 ,5-naphthylene group or a group in which X is a bridge member-SO or a linear or branched alkylene group containing one to four carbonatoms, and phenylene nuclei of the said groupings may contain one or twosubstituents 2 ,2 being an alkyl or alkoxy group contain ing one to fourcarbon atoms or a halogen atom, and m=0, l 5 or 2. In connection withthese and the preceding formulas it i should also be said that the alkylgroups mentioned may be branched so that compounds thus constituted maybe particularly valuable in certain cases.

As examples ofimportant types of compounds to be used in this inventionthe following bis-oxalic acid amide esters may be mentioned:m-phenylene-bis-(oxalamido-y-chloropropyl ester),m-phenylene-bis-(oxalamido-methyl ester),p-phenylene-bis-(oxalamido-isoamyl ester),p-phenylene-bis-(y-cyanopropyl ester),p-phenylene-bis-(oxalamido-dodecyl ester),

(6-methyl-l ,3-phenylene)-bis-(oxalamido-crotyl ester), (2,5-dichlorol,4-phenylene)-bis-(oxalamido-butyl ester), (2,5-dimethoxyl,4-phenylene)-bis-(oxalamido-methyl ester),

(2,5-dimethyl-l ,4-phenylene )-bis-( oxalamido-ethoxyethyl ester),

4,4-diphenylene-bis-(oxalamido-butyl ester),4,4'-diphenylene-bis-(oxalamido-y-phenylpropyl ester),4,4-diphenylene-bis-(oxalamido-p-chlorobenzyl ester),(3,3-dimethyl-4,4-diphenylene)-bis-(oxalamido-isobutyl ester),

(3,3 '-dimethoxy-4,4'-diphenylene )-bis-(oxalamido-methyl ester),(3,3'-dimethoxy-4,4'-diphenylene)-bis-(oxalamido-p-methylbenzyl ester),

4,4-bis-(oxalamido-undecyl ester)-diphenylsulphide,4,4'-bis-(oxalamido-cyclohexyl ester)-diphenylether, 354,4-bis-(oxalamido-n-octadecyl ester)-diphenylsulphone, 4,4'-bis-(oxalamido-ethoxyethyl ester)-diphenylmethane.

The compounds described above are accessible by known processes. Themost important method of manufacturing the compounds of the formula (2)which are of importance to industry and have symmetric constitution withrespect to the residues A consists in reacting 1 mol of a diamine of theformula (7) NH. .W,-llH with 2 mols of an oxalic ester of the formula(8) A -OCOCOY in which W and A have the above meanings and Y, representsan alkoxy group which preferably contains one to six carbon atoms, or isa halogen atom, by allowing them to react at a temperature within therange from 0 to 200 C.; the esterification is preferably conducted inpresence of excess oxalic ester, whereby the residue A can be exchangedfor another residue A by trans-esterification, and, if desired, in asolvent that is chemically inert towards the reactants. if this reactionis accompanied by elimination of an alcohol, it is advantageouslyremoved from the reaction mixture by distillation, provided its boilingpoint allows this.

The reaction, which is preferably performed in presence of an excess ofoxalic ester, is carried out with special advantage with an up to 2-foldmolecular excess.

The procedure described above is especially applicable to themanufacture of compounds of the formula (5), reacting l mol ofa diamineof the formula 65 with 2 mols of an oxalic ester of the formula in whichW and A, have the above meanings and Y represents an alkoxy groupcontaining one to six carbon atoms.

According to a preferred variant the condensation of the diamine of theformula (7a) with an oxalic acid diester of the formula (9) or (8) iscarried out in presence of anhydrous boric acid (preferably 0.02 to 0.1mol for every mol of diamine) at a temperature from to 130 C. Suitablesolvents that are inert towards the reactants should as far as possiblebe solvents for both reactants and have a boiling point of at least C.Such solvents are, for example, chlorobenzenes, tetrachloroethane,xylenes, ethylamyl ketone, diethyleneglycol diethyl ether or isophorone.

According to another process for the manufacture of the compounds to beused in this invention, for example those of the formula (2), a diamineof the formula (7) is reacted with an oxalic ester halide ofthe formulawhere A has the above meaning and Hal is a halogen atom, especially achlorine atom. In these cases it is advantageous to use a solvent thatboils between 30 and C., is inert towards the reactants and is speciallycapable of dissolving the diamine of the formula (7), such as benzene,toluene, acetone, ethyl acetate or dioxan. This reaction may beperformed without a condensing catalyst; the temperature to bemaintained ranges from 0 to C., preferably from 20 to 80 C. As a rule,an equivalent quantity of the reactant of the formula (10) suffices,that is to say 2 mols thereof for every mol of diamine.

According to a variant which is specially valuable to the manufacture ofcompounds of the above formulas the bis-oxalic acid amide esters aretrans-esterified on the ester bond, that is to say a residue A A A, or Ais exchanged for a differently constituted residue covered by the samedefinition, advantageously in presence of a known trans-esterifyingcatalyst.

This trans-esterification process is specially valuable to themanufacture of compounds of the formula (6): A compound of the formula(5) A,,-O-CO-CONH--W NHCO--COO 4 in which A, represents an alkyl groupcontaining one to six carbon atoms and W a 1,3- or l,4 phenylene group,a 4,4- diphenylene group, a 1,4- or 1,5naphthylene group or a groupwhere X is a bridge member SO or a linear or branched alkylene groupcontaining one to four carbon atoms, and phenylene nuclei of the saidgroupings may contain one or two substituents Z ,Z being a halogen atomor an alkyl or alkoxy group containing one to four carbon atoms, andm=0, l or 2 is reacted with an alcohol of the formula (1 l) A OH inpresence of a trans-esterifying catalyst in a solvent, at a temperatureranging from 80 to 200 C,

Suitable trans-esterifying catalysts are, for example, strong alkaliessuch as alkali metal alcoholates and alkali metals or acid catalystssuch as hydrochloric acid, concentrated sulphuric acid,p-toluenesulphonic acid and the like, which are used in catalyticamounts, that is to say in an amount of about 0.0l mol or 0.2 molcalculated from the grouping to be transesterified.

Solvents suitable for the trans-esterification are quite generally allthose mentioned above, except that their boiling point should be from 80to 200 C. It is of course also possible to use as solvent the alcohol ofthe formula (11). Further suitable are ketones and halobenzenes.

Starting materials suitable for trans-esterification reactions are moreespecially compounds of the formula (2) in which A is an alkyl radicalcontaining up to six carbon atoms, preferably methyl or ethyl.

By using the corresponding alcohols it is possible to introduce by thetrans-esterification more especially the residues of alcohols such asbutanol, Z-ethylhexyl, dodecyl,

octadecyl, isoamyl, benzyl, allyl, cyclohexyl or y-chloropropyl alcohol.

In view of the fact that the trans-esterification is an equilibriumreaction it is advantageous to use an excess of the alcohol whoseresidue is to be introduced. in general, a 0.05 to 0.3 molar excess willsuffice;

Depending on the reactivity of the alcohol concerned thetrans-esterifying temperature ranges from about 50 to l80 C.; to preventany undesired side-reactions the temperature should if possible be keptbelow 130 C., preferably between 100 and 130 C. To promote the progressof the reaction the alcohol liberated from the starting material shouldbe more volatile than the alcohol to be introduced and it shouldadvantageously be continuously removed from the system, for example byblowing itout with an inert gas, such as a current of nitrogen.

With the aid of the compounds of the above formula (1) and of thefollowing formulas it is possible principally to stabilize and protectall those organic materials which are in any form damaged or destroyedby the action of ultraviolet rays. Such damages caused by the identicalagency, namely ultraviolet irradiation, may have widely differingresults, for example changes in color, changes in the mechanicalproperties (brittleness, fissuring, tear strength, flexural strength,abrasive strength, elasticity, ageing), triggering off of undesiredchemical reactions (decomposition of sensitive chemical substances, forinstance of medicaments, photochemically induced rearrangements,oxidation or the like, for example of oils containing unsaturated fattyacids), causing of burns and irritations (for example on human skin),and the like. The oxalic acid derivatives defined above are preferablyused to protect polycondensates and polyadducts from the effects ofultraviolet rays. ln addition, a rather large number of the compoundsdefined above have in addition to the ultraviolet stabilizing activityalso a stabilizing effect against the action of oxygen and heat and theyalso possess antistatic properties.

The organic materials to be protected may be in a wide variety ofprocessing stages and physical states, their common characterizingfeatures being their sensitivity towards ultraviolet rays.

As substances of low or high molecular weight that can be protected orstabilized by the present process there may be mentioned, for example,without intending any limitation thereto: Organic natural substancessuch as are used for pharmaceutical purposes (medicaments),ultraviolet-sensitive dyestuffs, compounds which as victuals or invictuals are decomposed by the action of light (unsaturated fatty acidsin oils) and the like.

As examples of organic substances of high molecular weight the followingmay be mentioned: (l) Synthetic organic materials of high molecularweight, such a. Polymers based on organic compounds containing at leastone polymerizable carbon-to-carbon double bond, that is to say theirhomoor copolymers and their aftertreated products, for examplecross-linking, grafting or degradation products; polymer dilutions;products obtained by modifying reactive groupings in the polymermolecule, such for example as polymers based on a,B-unsaturatedcarboxylic acids (e.g., acrylates, acrylamides, acrylonitrile), ofolefin hydrocarbons e.g., a-olefins, ethylene, propylene or dienes,i.e., also rubbers and rubberlike polymers (also so-called ABSpolymers); polymers based on vinyl and vinylidene compounds (e.g.,styrene, vinyl esters, vinylchloride, vinyl alcohol), of

halogenated hydrocarbons, of unsaturated aldehydes and ketones, allylcompounds and the like; I

b. other polymers as obtained e.g., by ring opening, e.g., polyamides ofthe polycaprolactam type; furthermore formaldehyde polymers, of polymersaccessible by polyaddition as well as polycondensation, such aspolyethers, polythioethers, polyacetals, thioplasts.

c. Polycondensates or precondensates based on bifunctional orpolyfunctional compounds containing condensible groups, their homoandcocondensates and aftertreated products, for example: Polyesters[saturated (e.g., polyethylene terephthalate) or unsaturated (e.g.,maleic acid-dialcohol polycondensates and their cross-linked productswith copolymerizahle vinyl monomers), linear or branched (also thosebased on higher hydric alcohols, e.g., alkyd resins)], polyamides (e.g.,hexamethylenediamine adipate), maleinate resins, melamine resins, phenolresins (e.g., novolaks), aniline resins, furan resins, carbamide resinsand their precondensates and analogously constituted products;polycarbonates, silicone resins and others.

d. Polyadducts such as polyurethanes (cross-linked or not), epoxyresins.

ll. Semisynthetic organic materials such, for example, as celluloseesters or mixed esters (acetate, propionate), nitrocellulose, celluloseethers, regenerated cellulose (viscose rayon, cuprammonium cellulose) ortheir aftertreated products or casein synthetics.

Ill. Natural organic materials of animal or vegetable origin, e.g.,based on cellulose or proteins such as wool, cotton, silk. bast,jute,hemp, furs and hairs, leathers, wood pulp in fine distribution, naturalresins (such as colophony, especially lacquer resins, gelatin, glues;also rubber, gutta percha, balata and their aftertreated and modifiedproducts, degradation products, products accessible by modification orreactive groups.

The organic materials concerned, especially plastics of the type ofvinylchloride polymers, saturated and unsaturated polyesters, cellulosesand polyamides, may be at a wide variety of processing stages (rawmaterials, semifmished or finished products) and physical states. Theymay in the form of a wide variety of shaped articles, that is to saye.g., predominantly three-dimensional objects such as sections,containers or various workpieces, chips or granulates or foamedarticles; predominantly two-dimensional structures such as films, foils,lacquers, impregnations or coatings or predominantly unidimensionalproducts such as filaments, fibers, flocks, bristles or wires. The saidmaterials may also be in unshaped states in a wide variety ofhomogeneous or inhomogeneous forms of distribution and physical states,being, for example, powders, solutions, normal or reversed emulsions(creams), dispersions, latices, sols, gels, putties, waxes, adhesives orgrouting compositions.

Fibrous materials may be in a wide variety of predominantly nontextileprocessing forms, being for instance threads, yarns, fiber fleeces,felts, paddings, flocculated structures, or textile fabrics or textilecomposites, knitwear, paper, cardboards or the like.

The new stabilizers may be used, for example, as follows:

a. In cosmetic preparations such as perfumes, dyed or undyed soaps andbath salts, skin and face creams, powders, repellants and especiallysunburn oils and creams;

b. in admixture with dyestuffs or pigments or as additives to dyebaths,printing, discharge or reserve pastes; also for aftertreating dyeings,prints or discharge prints;

0. in admixture with so-called carriers, antioxidants, other lightfilters, heat stabilizers or chemical bleaches;

d. in admixture with cross-linking agents, dressings agents such asstarches or synthetic dressing agents;

e. in combination with detergents; the detergent and the stabilizer may,if desired, be added separately to the washing liquor;

f. in gelatin layers for photographic purposes;

g. in combination with polymeric vehicles (polymers, polycondensates orpolyadducts) in which the stabilizer, if desired side by side with othersubstances, is incorporated in dissolved or dispersed form, e.g., incoating, impregnating or binding agents (solutions, dispersions,emulsions) for textiles, fleeces, paper, leather;

h. as additives to a wide variety of industrial products to reduce theirageing tendency, for example as additives to glues, adhesives, paints orthe like.

When the protecting agents of this invention are to be used for treatingorganic textile materials of natural or synthetic origin, e.g., textilefabrics, theyv may be applied to the substrate to be protected at anydesired phase of the final processing, such as during a dressing,anticrease finishing, dyeing or other finishing operation by fixingmethods similar to dyeing processes.

The new stabilizers to be used according to this invention arepreferably added to or incorporated with the materials before or duringthe shaping of the latter. Thus, for example, in the manufacture offilms, foils, tapes or shaped structures they may be added to themoulding or injection mounting composition or dissolved, dispersed or inany other suitable manner finely distributed in the spinning compositionbefore it is spun. The protective agents may also be added to thestarting substances, reaction mixtures or intermediate products used forthe manufacture of fully synthetic or semisynthetic organic materials,hence also before or during the chemical reaction, for example in thecourse of a polycondensation (hence also to precondensates), apolymerization (hence also to prepolymers) or a polyaddition.

An important sphere of application of the stabilizers of this inventionis their incorporation with a protective layer used to protect amaterial placed behind it. This can be achieved by applying theultraviolet absorber to the surface layer (of a film, a fiber ormultidimensional structure), for example similar to a dyeing process, orthe active substance may be incorporated witha polymer (polycondensateor polyadduct) film by a known surface treating method with polymericsubstances, or the active substance may be dissolved in a suitablesolvent and allowed to diffuse or swell into the surface layer.According to another important variant the ultraviolet absorber isincorporated with a self-supporting, substantially two-dimensionalsupport, e.g., a foil or the wall ofa vessel, in order to ward offultraviolet rays from the substance placed behlnd the support (examples:shopwindows, films, transparent wrappers, bottles).

From the foregoing it is obvious that not only the substrate or supportincorporating the ultraviolet absorber is protected but also otheraccompanying ingredients of the substrate, for example dyestuffs,antioxidants, disinfectants antistatics and other dressings,plasticizers and fillers.

Depending on the type of substance to be protected or stabilized, on itssensitivity or on the form in which the protection or stabilization isachieved the requisite quantity of stabilizer may vary within widelimits, for example from about 0.01 to 10 percent by weight, referred tothe weight of substrate to be protected. For most practical purposes aproportion of about 0.05 to 2 percent will suffice.

Accordingly, the process for protecting organic materials from theeffects of ultraviolet irradiation and heat as described above consistsin homogeneously distributing the compounds defined above in the organicmaterial to be protected, or in applying them to the surface of thematerial or in covering the material with a filter layer that containsthe compounds defined above.

This is most advantageously done by homogeneously distributing thecompounds described in substance or as a solution or dispersion in theorganic material to be protected in an amount of 0.01 to l percent,preferably 005 to 2.0 percent, by weight, referred to the weight of thematerial to be protected before the latter is given its final shape.

When the substances of this invention are to be applied superficially tothe substrate to be protected, for instance to a fibrous material(fabric), this is advantageously done by immersing the substrate to beprotected in a liquor that contains the ultraviolet absorber indissolved or dispersed form. Solvents suitable for this purpose are, forexample, methanol, ethanol, acetone, ethyl acetate, methylethyl ketone,cyclohexanol or especially water. As is done in dyeing, the substrate isleft in the liquor for a certain time-generally, minutes to 24 hourswill sufficeat 10 to 120 C.; if desired, the liquor may be moved aboutduring this period of time. The material is then rinsed, if desiredwashed and dried.

I found:

In many cases it is found advantageous to use the abovementioned lightfilters in combination with sterically hindered phenols, esters ofthiodipropionic acid or organic phosphorus compounds.

Unless otherwise indicated, all parts in the following examples are byweight.

MANUFACTURING INSTRUCTIONS A. A mixture of 54 parts ofl,4-phenylenediamine, 292 parts of oxalic acid diethyl ester and 2 partsof boric acid is heated to 120 C. Within 6 to 8 hours 35 to 40 parts ofethanol pass over. The reaction mixture is subjected to steamdistillation.

Yield:(pure): to parts of the compound melting at 220 to 22 C. (fromdioxane+cyclohexane Analysis: calculated: C 54.56 H 5.0] N 9.06

found: C 54.54 H 5.23 N 9.09

B. 28 Parts of oxalyl monochloride monoethyl ester in 250 parts oftoluene are stirred dropwise within 30 minutes at 60 C. into a solutionof 36.8 parts of 4,4'-diaminodiphenyl in 500 parts of toluene, and thewhole is then heated for another 2 hours at 85 to 90 C. After steamdistillation there are obtained 65 to 70 parts of the product of theformula in substantially pure form. A specimen recrystallized fromdichlorobenzene melts sharply at 225 to 227 C. and reveals the followinganalytical data:

calculated: N 7 .29

| l NH-Q-QNH-C 0 c 0-0-cim settle out; it is chromatographically pureand melts at to l56 C. after strong sintering at l45 to l47 C.

Analysis: calculated:

found:

The products listed in the following table were manufactured in a mannersimilar to that described under A and B above. The melting point in C.is shown in volume IV and the analytical values for C, H and N in volumeV (upper line: calculated, lower line: found).

3,639,249 11 1: EXAMPLE I EXAMPLE II A solution of 0.] part of sodiummetal in 60 parts of n-oc- A m u of 13-4 parts f lh C mp 1 1 Parts ftanol is heated to 125 to 130 C., l3.4 parts of the compound stearylalcohol. 0.25 part of sodium methylate and l75 parts of the formula (16)are added and the whole is stirred for 2 5 of toluene is reacted withstirring for9 hours at 100 to l05C. in an open vessel, and then foranother 2 days under reflux. The hot reaction solution is filteredclear, mixed at 80 C. with 80 parts of alcohol, cooled and suctioned.Yield: 18.5 parts (from benzine) of the compound of the formula 10 (35)IIsC 0 mo 0 0 on. Hu-cn-oo 0c ONHQ NILCOCOOC'H" melting at ll6t0 117C.

[5 Analysis:

calculated: C 72.6l H 9.93 found: C 72.79 H [0.06

The compounds listed in the following table were prepared in a mannersimilar to that described in examples I and ll; the A -l i-- 20 meltingpoint in C. is shown in column IV and the analytical calculated y. c66.64 H 1. N 457 data for C, H and N in column V (upper line:calculated, lower found: c 66.45 H 7.57 N 4.74. line; found).

TABLE I (38) VzOOCCONH-WsNHCOCOOV2 II (V z=) 111 F) 1V H300 OCH: CH2

HtC--OGH2CH2 164-165 HzC-CH-CH1 H 00 0011, 227428 g}.

HgCO OCH;

hours at this temperature in an open vessel, then cooled to roomtemperature; 50 parts of ethanol are added, the whole is cooled for lhour in ice, suctioned and the residue is rinsed with 50 parts ofalcohol. Recrystallization from benzine furnishes l2 parts of thecompound ofthe formula HnCaO-COCONH melting at l28-l29 C.

2 mm we on no no mo uu m mm an.

s 87 7 7 66 5d 7 7 6 7 6 6 as as 7 7 mm mm on on um am we no mm mm mm Ame um mm mm mo m ow we do we l (0 cl Ill I) (l a 4 m m m H H w H m m w wm 1 H u z H l 1 c .0 c 0 U w c o l 1 0 o H n n H m w c c c c m r m n 1 w1 P. w H m c m m .,.lI H H 0 C C H 5 C C 5 r C H h H H 9 9 9 z I l n n HH m w o m o m m olo m C C C a z e a a .m r H a u u "m H H H H H H m H HH C c 0 C C 0 C C 0 o C C a Q a u u a a u m m "T'AnLi': (so V100CGONllW5-NH-COCOOV2 l n w: 1 1(Wy 1v v 1| 4mm") oua 7.80 4.93 a1. 44 1. n2 4.s1

12 (t)ll tJll,t));---UII UII; moo cm 1084" g gag 3.11):

18 aII11(n) gag; w; 2.5:

mo- CH cm c s s. 1 67. 7. 99

2 5 N.H 113414 67.70 1. 94 1. 4 -mn-oncrn ;o1n

PAT. N0. 3639240F. 298

75 s 11( 1 3344 2H3 76 *CEHWQ HBC 82-83 3;;gg ;;gg g;

11 O12Hz5(n) 69. 1a 9.10 4.65 CH; i 69. 00 0. 65 4. s5

EXAMPLES OF APPLICATIONS ln each of the following examples ofapplication a typical representative of the respective subgroup ofcompounds of this invention was used. In principle, all compoundsmentioned in the preceding description and their equivalents are equallysuitable. except that the solubility of the compound chosen in thesubstrate to be used must be taken into consideration or firstdetermined by a small-scale test. Moreover, it should be mentioned inthis context that compounds, in which in the central member the two arylnuclei are connected by an intermediate member X, absorb by about my.less towards the visible light, and this must likewise be taken intoconsideration to suit the individual application.

EXAMPLE l An acctylccllulose film about 50;; thick is produced bycasting a 10 percent acetonie acetylcellulose solution containing lpct'tcnl (calculated from the acctyleellulose) of the contponndol'l'orlnula l2 After drying. the following percentage lighttransmission values are obtained:

EXAMPLE 2 A paste prepared from parts of polyvinylchloride, 59 parts byvolume of dioctylphthalate and 0.2 part of the compound of the formulaI3) is calendered at 145 to 150 C. to form a foil about 0.5 mm. thick.The polyvinylchloride foil obtained in this manner absorbs completelywithin the ultraviolet region from 280 to 360 mp.

Instead of the compound of the formula l3) there may be used, forexample, a compound of one of the following formulas: l2, I9, 23, 24 to28, 34, 39, 42 to 50, 52, 55, 56,57 or 63 to 73.

EXAMPLE 3 A mixture of I00 parts of polyethylene and 0.2 part of thecompound ol' the formula (34) is calendered at to C. to form a foilwhich is then pressed at l50 C.

The polyethylene l'oil obtained in this manner is substantiallyimpermeable to ultraviolet light within the region from 280 to 360 mp.

Instead of the compound of the formula 34 there may be used, forexample, a compound of one of the following formulas: l2, 19, 22, 35,39, 52, 60, 66 or 67.

EXAMPLE 4 A mixture of 100 parts of polypropylene and 0.2 part of one ofthe compounds of the formulas 24, 26, 27, 34, 35, 41, 50, 57, 59, 68 or69 is calendered at l70 C. to form a sheet which is then pressed at 230to 240 C. under a maximum pressure of40 kg./em. to form a panel I mm.thick.

The resulting panels are impermeable to ultraviolet light within theregion from 280 to 360 mu. Other compounds listed in the table display asimilar behavior.

EXAMPLE 5 A solution of 0.2 part of the compound of the formula (34) in1.8 parts of monostyrene is mixed with 0.5 part of a solution of cobaltnaphthenate in monostyrene (containing l percent of cobalt). Then 40parts of an unsaturated polyester resin based on phthalic acid+maleicacid+ethyleneglycol in monostyrene are added and the whole is stirredfor l minutes. 1.7 Parts of a catalyst solution (methylethyl ketoneperoxide in dimethyl-phthalate) are dropped in and the well stirred,air-free mass is poured in between two plates of glass. After 20 minutesthe polyester panel of 1 mm. thickness has solidified sufficiently toenable it to be taken out of the mould. lt is impermeable to ultravioletlight within the region from 280 to 370 mp" The compound of the formula34 may be replaced, for example, by one of the compounds of the formulas26, 28, 31, 43,50, 51,59,60,6l,68 or 70.

EXAMPLE 6 25 Grams of distilled monostyrene are prepolymerized in astoppered bottle for 2 days at 90 C. in a heating cabinet, and then 0.25g. of one of the compounds of the formulas 26, 28, 34, 42, 43, 50, 51,68 or 69 and 0.025 g. of benzoyl peroxide are slowly stirred into theviscous mass. The mixture is then poured into a cube-shaped mould ofaluminum foil and heated for 1 day at 70 C. After the mass hascompletely solidified and cooled off, the mould is broken up. The blockis then pressed in a hydraulic press at a temperature of 138 C. under apressure of l50 kg./cm. to form a panel 1 mm. thick.

The polystyrene panels manufactured in this manner are impermeable toultraviolet light within the region from 280 to 370 my" They arecompletely colorless.

EXAMPLE 7 10,000 parts of a polyamide, manufactured in known manner fromcaprolactam, in chip form are mixed for 12 hours in a tumbler with 30parts of one of the compounds of the formulas 21, 35, 38, 43, 60, 67 or70. The chips treated in this manner are melted in a boiler, from whichthe atmospheric oxygen has been displaced with superheated steam andwhich is heated at 300 C., and the melt is stirred for one-half hour.The melt is then expressed under a nitrogen pressure of atmospheres(gauge) through a spinneret and the spun and cooled filament is wound upon a spinning bobbin, whereby it is at the same time stretched.

The degradation of the macromolecules caused by the exposure in thefadeometer and measured by the relative viscosity in concentratedsulphuric acid is substantially reduced by the addition of the abovecompounds.

Other compounds listed in the table display a similar behavior.

EXAMPLE 8 0.2 Gram of the compound of the formula (18) is dissolved inl0 g. of pure olive oil. A 50 u thick layer of this solution absorbsultraviolet light up to 330 mp. completely.

ln identical manner other fatty oils and creams or emulsions used forcosmetic purposes may be used for dissolving the compounds referred toabove.

Instead of the compound ofthe formula 18) there may be used, forexample, the compound of the formula 2l, 34, 43, 50, 57 or 58.

EXAMPLE 9 l2 Grams of polyacrylonitrile are strewn with stirring into 88g. of dimethylformamide until all has dissolved. They 0.1 g. of acompound, for example of formula 35, which dissolves immediately, isadded. The viscous mixture is then applied to a cleaned plate of glassand spread out with a film drawing rod. The treated plate of glass isthen dried for 20 minutes at 120 C. in a vacuum drying cabinet under apressure of I50 mm. Hg. A foil is obtained which has a thickness ofabout 0.05 mm. which is easy to pull OK the glass plate; it iscompletely colorless and absorbs ultraviolet light up to a wavelength of350 mp. substantially completely, whereas a foil that does not containthe above compound of the formula 35 passes at least percent of theultraviolet light. Incidentally, the compounds mentioned in connectionwith polystyrene may likewise be incorporated with polyacrylonitrile.

We claim:

1. A process for protecting organic materials selected from the groupconsisting of organic polymeric materials from the action of ultravioletrays, which comprises applying to said materials from 0.0l to 10 percentby weight of a bis-oxalic acid amide ester corresponding to the formulaA -OCOCO--NH-W,-NH CO-COO-A in which A represents an alkyl, alkenyl,cycloalkyl or aralkyl radical containing up to 20 carbon atoms, whichdoes not displace the absorption maximum of these compounds to valuesabove 370 my. and which may also contain further substituents; Wrepresents a phenylene, diphenylene, naphthylene residue or a residue(zl)m 1):-

and the phenylene groups of these residues may contain one or twosubstituents Z Z being an alkyl or alkoxy group containing one to fourcarbon atoms, or a halogen atom or an 80 1-! group; m=0, or 2, and Xrepresents an alkylene group containing one to four carbon atoms or abridge member O-, S, NH- or S0 2. A process according to claim I,wherein a symmetric bisoxalic acid amide ester of the formula is used inwhich A, represents an alkyl group containing one to l8 carbon atoms, aphenylakyl group whose alkyl residue contains one to four carbon atoms,an alkoxyalkyl group with one to l2 carbon atoms and preferably one tothree --O bridges, an alkenyl group containing one to four carbon atomsor a cyclohexyl group, and W represents a l,3- or l,4-phenylene, a4,4'-diphenylene or a l,4- or 1,5-naphthylene group or a group in whichX represents a bridge member-SO,- or a linear or branched alkylene groupcontaining one to four carbon atoms and phenylene nuclei of theaforesaid groupings may contain one or two substituents Z 2 beinghalogen or an alkyl or alkoxy group containing one to four carbon atoms,and m=0, l or 2.

3. A process according to claim 1, wherein a symmetric bisoxalic acidamide ester of the formula is used, in which A, represents an alkylgroupcontaining one to 18 carbon atoms, a phenylalkyl group whose alkylresidue contains one to four carbon atoms, an alkoxyalkyl groupcontaining one to 12 carbon atoms and preferably one to three 0-bridges, an alkenyl group containing one to four carbon atoms or acyclohexyl group, and W represents a 1,3- or 1,4- phenylene, a4,4-di-phenylene or l,4- or 1,5-naphthalene group, and phenylene nucleiin the aforesaid groupings may contain one or two substituents Z Z beinga halogen atom or an alkyl or alkoxy group containing one to four carbonatoms.

4. A process according to claim 1, wherein a symmetric bisoxalic acidamide ester is used which corresponds to the formula in which Arepresents an alkyl group containing one to six carbon atoms and W a1,3- or 1,4-phenylene, a 4,4'-diphenylene or l,4- or 1,5-naphthylenegroup or a group in which X represents a bridge member SO or a linear orbranched alkylene group containing one to four carbon atoms andphenylene nuclei of the aforesaid groupings may contain one or twosubstituents Z 2 being halogen or an-alkyl or alkoxy group containingone to four carbon atoms, and m=0, l or 2.

5. A process according to claim 1, wherein a symmetric bisoxalic acidamide ester of the formula is used in which A represents an alkyl groupcontaining seven to 18 carbon atoms. a phenylalkyl group whose alkylresidue contains one to four carbon atoms, an alkoxyalkyl groupcontaining one to eight carbon atoms and one to three oxygen bridges, anallyl or cyclohexyl group, and W represents a 1,3- or 1,4-phenylenegroup, a 4,4'-diphenylene group, a 1,4- or l,5-naphthylene group or agroup in which X represents a bridge member SO or a linear or branchedalkylene group containing one to four carbon atoms and phenylene nucleiof the aforesaid groupings may contain one or two substituents Z Z beinghalogen or an alkyl or alkoxy group containing one to four carbon atoms,and m=0, l or 2.

6. Organic polymeric materials containing 0.01 to 10 percent, by weight,referred to the organic material of at least one bis-oxalic acid amideester as defined in claim 1 as an ultraviolet absorber.

2. A process according to claim 1, wherein a symmetric bis-oxalic acidamide ester of the formula A3-O-CO-CO-NH-W2-NH-CO-CO-O-A3 is used inwhich A3 represents an alkyl group containing one to 18 carbon atoms, aphenylakyl group whose alkyl residue contains one to four carbon atoms,an alkoxyalkyl group with one to 12 carbon atoms and preferably one tothree -O- bridges, an alkenyl group containing one to four carbon atomsor a cyclohexyl group, and W2 represents a 1,3- or 1,4-phenylene, a4,4''-diphenylene or a 1,4- or 1,5-naphthylene group or a group in whichX2 represents a bridge member -SO2- or a linear or branched alkylenegroup containing one to four carbon atoms and phenylene nuclei of theaforesaid groupings may contain one or two substituents Z2, Z2 beinghalogen or an alkyl or alkoxy group containing one to four carbon atoms,and m 0, 1 or
 2. 3. A process according to claim 1, wherein a symmetricbis-oxalic acid amide ester of the formulaA3-O-CO-CO-NH-W3-NH-CO-CO-O-A3 is used, in which A3 represents an alkylgroup containing one to 18 carbon atoms, a phenylalkyl group whose alkylresidue contains one to four carbon atoms, an alkoxyalkyl groupcontaining one to 12 carbon atoms and preferably one to three -O-bridges, an alkenyl group containing one to four carbon atoms or acyclohexyl group, and W3 represents a 1,3- or 1,4-phenylene, a4,4''-di-phenylene or 1,4- or 1,5-naphthalene group, and phenylenenuclei in the aforesaid groupings may contain one or two substituentsZ2, Z2 being a halogen atom or an alkyl or alkoxy group containing oneto four carbon atoms.
 4. A process according to claim 1, wherein asymmetric bis-oxalic acid amide ester is used which corresponds to theformula A4-O-CO-CO-NH-W2-NH-CO-CO-O-A4 in which A4 represents an alkylgroup containing one to six carbon atoms and W2 a 1,3- or 1,4-phenylene,a 4,4''-diphenylene or 1,4- or 1,5-naphthylene group or a group in whichX2 represents a bridge member -SO2- or a linear or branched alkylenegroup containing one to four carbon atoms and phenylene nuclei of theaforesaid groupings may contain one or two substituents Z2, Z2 beinghalogen or an alkyl or alkoxy group containing one to four carbon atoms,and m 0, 1 or
 2. 5. A process according to claim 1, wherein a symmetricbis-oxalic acid amide ester of the formulaA5-O-CO-CO-NH-W2-NH-CO-CO-O-A5 is used in which A5 represents an alkylgroup containing seven to 18 carbon atoms, a phenylalkyl group whosealkyl residue contains one to four carbon atoms, an alkoxyalkyl groupcontaining one to eight carbon atoms and one to three oxygen bridges, anallyl or cyclohexyl group, and W2 represents a 1,3-or 1,4-phenylenegroup, a 4,4''-diphenylene group, a 1,4- or 1,5-naphthylene group or agroup in which X2 represents a bridge member -SO2- or a linear orbranched alkylene group containing one to four carbon atoms andphenylene nuclei of the aforesaid groupings may contain one or twosubstituents Z2, Z2 being halogen or an alkyl or alkoxy group containingone to four carbon atoms, and m 0, 1 or
 2. 6. Organic polymericmaterials containing 0.01 to 10 percent, by weight, referred to theorganic material of at least one bis-oxalic acid amide ester as definedin claim 1 as an ultraviolet absorber.